Allen-bradley Company, LLC

Michael R Havey

Anthony Gerard Gibart

Daniel J Bolda

Joel C Clemente

Michael A Feavel

John J Gilge

A fuse blown detection circuit for use in conjunction with the control transistor output circuits of a programmable controller which provides low leakage after the fuse is blown. The detection circuit comprises a pair of voltage dividers and a diagnostic triggering device forming an H-bridge network connected across the terminals of the fuse and a blocking diode. When the fuse is blown the voltage levels defined by the dividers change to activate the trigger device and enable a diagnostic signal indicative of the fuse blown condition while the blocking diode prevents current flow back through the control transistor and output circuit.

Low leakage fuse blown detection circuit

A flash-on reduction circuit for use in the binary state output circuitry of an industrial controller employs a current conductor to charge parasitic capacitances of the output circuitry when the industrial controller is first turned on and a current limiter for preventing high current flows through the output power stages of the output circuit when the industrial controller is first turned on. The current limiter is deactivated by a timing means after the parasitic capacitances have been charged by the current conductor. In a first embodiment, the current conductor and current limiting means are provided by a current source applying increasing power to the output circuit.

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Hartland, WI, United States of America

Michael R Havey